High frequency circuit selector



Oct. 16, 1934. M. MORRISON 1,977,398

HIGH FREQUENCY CIRCUIT SELECTOR Filed May 51, 1930 3 Sheets-Sheet l Oct.16, 1934. M. MORRiSON HIGH FREQUENCY CIRCUIT SELECTOR Filed May 51, 19303 Sheets-Sheet 2 Oct. 16, 1934. MORRISON 1,977,398

' HIGH FREQUENCY CIRCUIT SELECTOR Filed May 51, 1930 3 Sheets-Sheet 3than do the prior disclosures.

Patented get. 16, 1934.

UNITED STATES PATENT OFFICE This application is in part a part of, orrelated to, co-pending applications Serial Numbers 421,-

790 filed January 18, 1930, 445,593 filed April 19,

1930, 445,980 filed April .21, 1930, 449,216 filed 5 May 2, 1930,449,515 filed May.3, 1930, and 453,-

672 filed May 19, 1930.

This invention relates to a class of devices known as circuit selectorsand circuit distributors, particularly to devices adapted to work incircuits employing frequencies too high for practical operation ofmechanically moving parts; and has further application where quicknessof response, independent of frequency, is important.

Among the objects of this invention are; to provide a, deviceandcircuits therefor adapted to function as a circuit selector having nomechanically moving parts and thereby eliminating the difficultiesattendant thereto; to provide such a device with operatingcharacteristics devoid of inertia, making'it practically instantaneousin response to the control circuits; and to provide a selector devicesuitable for super-audio-frequency circuits and capable of providingcircuit selectivity for communication systems operable at any practicalfrequency of selectivity.

The above objects are general and typical of specific cases; further andother objects will be obvious to those skilled in the art upon readingthe specification and claims hereunder.

.JQ A distinguishing characteristic of this invention lies in the factthat the control field governing the periodicity of revolution of theelectric field in the present invention bears a different relation tothe number of anodes present Another distinguishing characteristic isthe fact that certain embodiments of the present invention may have onenumber of eflective control electrodes, and an entirely different andunrelated number of w anodes.

A further distinguishing characteristic is the fact that the controlcircuit, and the source of the circuit to be controlled, may bearbitrarily related.

The structural characteristics of embodiments hereunder constitutingelectron discharge devices, have been so fully disclosed in some of theprior applications cited above, that certain obvious practical detailswill not be stressed herein ,50 and the present invention will dealparticularly with the novelties of invention not already fully coveredin the above cited applications.

Fig. 1 is a diagram illustrating an electron device embodying thisinvention with illustrative circuits employed therewith, being theelectron introduced from a circuit 12.

discharge device employedin the systems disclosed in applications SerialNumbers 445,593 and 445,980 above referred to. Fig. 2 is a secondembodiment of this invention having certain operative advantages, andemploys electron discharge devices having structural characteristicsrelated to application Serial Number 421,- 790 above referred to. Fig. 3is a third embodiment of this invention employing an electron dischargedevice having structural characteristics related to Serial Number449,216 and Serial Number 453,672 above referred to.

In Fig. 1, 1 is an hermetically sealed envelope containing a filament 2,a screen 3, an anode 4, and two sets of parallel deflecting platesarranged at right angles 5 and 6 as is common practice in the art foruse in connection with cathode ray oscillographs; 1 t

7 is a filament battery, 8' is a filament rheostat, 9 is an anodebattery, 10 is a current-limiting resistor for the anode circuit.

The circuits for the elements described are those common in theoscillographic art with the following exceptions and additions: thecircuit for anode4 is provided with a means 11, for introducing circuitvariations in-series with the anode battery 9; whereby the voltage ofthe anode 4 may be caused to respond to variations This circuit may beused if and when desired, and jointly with another circuit hereinafterdescribed, or the two circuits may be used-independently of each other,as will be more fully discussed further on in the specification.

Plates 5 and 6 are provided for purposes of illustration with twosources of alternating current 13 and 14, which may be varied with re-'spect to voltage, frequency, wave-form and synchronous relation.

Within the envelope and along the same axis with the other electrodesalready described, are located a plurality of electrodes 15, 16, 17 and18, which may have any shape desirable, and a number subject tovariation depending upon the net result desired, and upon thecombination wave-forms from generators 13 and 14 as will be hereafterobvious. Electrodes 15, 16, 17 and 18 are provided with circuitsincluding a source of electrode potential 19, 20, 21 and 22, which areconnected through grid couplings 23, '24, 25, and 26 toa series of'threeelectrode electron discharge tubes 27, 28, 29 and 30, to a common lead'31, which is in turn connected to a means 32, for introducing circuitvariations from an' The electron discharge devices 27, 28, 29 and 30 areprovided with output circuits including 5 anode sources of potential 35,36, 37 and 38.

Circuit 12 may be eliminated fromthe operation of the device by closingswitch 39, and circuit 33 may be eliminated from the operation thereofby closing switch 40. g

In the operation of the embodiment in Fig. 1, the filament 2 is excited,and the anode 4 is provided with voltage, which causes an electronstream to emerge from filament 2, through screen 3, through anode 4,through plates 5 15 and 6, taking a path along the axis of the tube asis well known in oscillographic art.

By introducing circuit variations at 11, the change in anode potentialthereby affects the electron stream passing through 4 to a sumcientextent, to make it possible to repeat some of this effect in the outputcircuits, the anode 4 acting somewhat in the role of a controlelectrode, though in the actual operation described hereunder, switch 39is closed and switch 40 is open, introducing circuit variations at 32hereafter more fully described.

By the creating of direct current potentials in 19, 20, 21 and 22, theelectrodes 15, 16, 17 and 18 become the operating anodes for the device,and circuit variations introduced at 32 are in series with the maincircuit of the electron stream.

By the excitation of generators 13 and 14, the deflection of theelectron stream passing through parallel plates 5 and 6, is such as tocause the said electron stream to be deflected in such a circuitousmanner, as will cause the said'stream to traverse the electrodes in acertain predetermined order periodically. The order depending upon theirshape, arrangement, and the end result desired.

Any circuitous path across all of the electrodes may be used as long asthe frequency wave-form and phase relation of generators 13 and 14 aresuch as to make the said electron stream follow the desired path.

In the present embodiment, quarter-phase sine waves are assumed to beimpressed upon the Iplates 5 and 6, of such a value as to cause theelectron stream arising from filament 2 to take a circular path aroundthe electrodes 15, 16, 17 and 18, in the order named.

In some cases it is desirable to maintain synchronous relation betweencircuit'33, and, circuit 12 and the generators 13 and. 14. This may beaccomplished by any of the various tie-in methods suitable to theparticular embodiment used and some of which have been fully discussedin applications Serial Numbers 445,593 and 445,-

980 above cited.

In the embodiment under discussion, 33 is a circuit having a source ofpotential subject to variation the characteristics of which it isdesired to distribute into output circuits 35, 36,

37 and 38.

Generators 13 and 14 constitute a source of potential for the controlcircuit operating upon the electron stream at5 and 6.

' The electron stream provides a conductivity between the filament 2 andthe electrodes 15,

.16, 17 and 18, and the said electron stream, making one completecircuit of the electrodes for each complete period of one of thegenerators 13 or 14, so that the electron stream from 2 under thecontrol of generators 13 and 14 provides a continuity of circuit to thesaid electrodes during a time interval equal to one-fourth of the periodof the said control generators, so that the characteristics of circuitvariations introduced at 32 are directed ultimately to output circuit 35for the first quarter period of the con trol generators; to 36 for thesecond quarter period; to 37 for the third quarter period; and to 38 forthe last quarter period; and then this order is repeated.

It will be appreciated that with generators at 13 and 14, havingsuper-audio-frequencies of extremely high values, the device remainsoperative, because of the absence of inertia in the selector.

Where the generators 13 and 14. are tied-in synchronously with circuit33, synchronism between circuit 33 and the resultant output circuits 35,36, 37 and 38 is also maintainedthat is, the periodic repetitions in theoutput circuits are maintained in synchronism with the input circuit.

The embodiment shown in Fig. 1 is merely illustrative of the uses towhich the present invention may be put. The set-up as shown in thisfigure may be looked upon as providing an inertialess selectorrepresented by the tube 1 having all the controlled electrodes enclosedwithin the hermetically sealed envelope of the tube, and adapted todivide these variations up into a plurality of equally timed intervalsand distribute these divided portions consecutively and periodicallyinto a plurality of delivery circuits such as 35, 36, 37 and 38.

Such a general structure may be applied to telephony, telegraphy, to thetransmission of likenesses of images and other similar applica-- tions.Specific applications of such a selector device to the above mentionedfields are more fully covered in some of the above mentioned co-pendingapplications.

In Fig. 2, 41 is the terminal of a communication receiving apparatus; 42is the terminal apparatus thereof.

At the terminal 41 there is assumed to be received asuper-audio-frequency wave, constituting a communication-modulatedcarrier-wave, and an unmodulated carrier wave of a different frequency.43 is a'unit for separating the unmodulated carrier wave from thereceived wave, and delivering it to a transformer device 44. 45 is aunit for separating the communication modulated carrier wave from thereceived wave, and delivering it through coupling 63 to an electrondischarge device hereinafter described. The unmodulated wave received at44 is divided into two umnodulated waves, having a phase diiierence of90 electrical degrees, which is affected by a phase-splitter illustratedconventionally by a capacitor 46 and a reactor 47, which deliver totransformers 48 and 49 the said quarter-phase current. Transformers 48and 49 have secondaries 50 and 51, which are connected to anodes 52 and53, and to 54 and 55 respectively, through output circuit units 56, 57,58 and 59.

The anodes 52, 53, 54 and 55 for conventionality are illustratedas ringsegments, but which are formed in reality into segmental cylindricalsurfaces, and through the axis of these said surfaces is located a rodfilament 60 and all enclosed within an hermetically sealed envelope 61.all of which have structural details similar to the several electrondischarge devices in the above mentioned patent applications. Filament60 is provided with a filament battery 62, which is connected through ameans 63, for introducing the output of into the filament circuit. Thefilament circuit is further connected to the centers of the transformersand 51 as conventionally illustrated.

Units 56, 57, 58 and 59 may contain reception translating devices, and,sources of plate potential, if and when desired.

The unmodulated carrier wave received at 41 is applied to the anodes inthe form of a quarterphase revolving electric field and determines, inconjunction with the direction of the conductivity of the electrondischarge, and the circuit variation introduced at 63 due to thecommunication modulation discussed, to which of the several anodes thesaid circuit variation is directed and duration of the said directiondepending upon the periodicity and phase relation of the alternatingcurrent control field already described, as will be understood by thoseskilled in the art from the aforegoing disclosure.

The embodiment described in Fig. 1 utilizes a control field at rightangles to the electron discharge stream; and the embodiment described inFig. 2 employs a-control field in the same the introduction of a controlgrid into the electron discharge field, which provides means for moresensitive control than may be obtained in Fig. 2, and in addition towhich, amplification may be simultaneously effected. I

Equivalent elements of Fig. 3 have the same reference numerals used inFig. 2 for conciseness and clearness.

Instead ofthe output circuits of transformers 48 and 49 being connectedto the hollow cylin drical surface electrodes contained within thehermetically sealed envelope 61, the secondaries thereof are connectedthrough potentiometer control grid batteries 64, 65, 66 and 67 to beused if and when desired, to adjust the potentials of the grids enclosedin the envelope, 61. The grid structure utilized in 61 is of a form andcharacter fully disclosed in applications Serial Numbers 449,216 and453,672 above cited.

The output circuit units 56, 57, 58 and 59 in Fig. 3 are connected to aplurality of segmental cylindrical anodes similar to those of Fig. 2,and designated by 72, 73, 74 and 75, and have one terminal thereof eachconnected together, and to a common lead 68 tied in with the filamentcircuit at. the center of the secondaries 50 and 51. The secondaries 50and 51 are connected to a plurality of inter-meshed grids 76, 77, 78 and79 of the kind and character described in the first two preceding patentapplications referred to. Filament 69 for Fig. 3 may be a form dependingupon which type of inter-meshed grid structure is used; and for that ofthe figure, a straight rod similar to 60 provides an operativestructure.

The embodiment illustrated in Fig. 3 bears somewhat the relation to thatof Fig. 2, that a three electrode electron discharge device bears to atwo electrode electron discharge device.

The grids 76, 77, 78 and 79 act as control electrodes for the anodes 72,73, 74 and 75.

The quarter-phase unmodulated output of secondaries 50 and 51 produce arevolving control field, directing the electron stream against certainanode members 72, 73, 74 and 75, and depending upon the periodicity ofthe said unmodulated wave-forms, and thereby directing the modulatedcarrier current introduced at 63 into the output circuits 76, 77, 78 and79 in a predetermined order in cyclic form, as is fully understood fromcomparison with Fig. 2.

The above described embodiments have been.

reduced to simplest form consistent with clearness of disclosure. It isobvious to those skilled in the art that the structure herein describedis adaped to reversible operation-that is, the devices described maytake current from a single circuit and deliver it selectively to severalcircuits, or vice versa, the device may take current from severalcircuits and deliver it to a single one.

With special reference to Fig. 1, it will be noted that such details asfilament and grid batteries have been omitted as these are wellunderstood and may be brought into use by those skilled in the art whendesired. Particular attention is directed to the fact that although inFig. 1 the electron discharge device contained in 1 actually directs thecurrent through the said device to the several selective circuits, thatthis circuit is by no means a limitation of the invention hereunder andthat the grid-control electron-discharge tubes 27, 28, 29 and 30 mayreceive their super-audio-frequency modulated carrier-currents fromsources not including the electron discharge device contained in l as apart of the circuits thereof and the electron discharge device containedin 1 may merely act as a grid biasing device for the tubes 27, 28, 29and 30, causing the said tubes to become operative in a predeterminedand cyclic order by providing grid biasing for the said tubes in thedesired order.

These modifications are given as illustrative examples of practicalvariations in embodiments, but the scope of this invention is bestdescribed in the claims hereunder.

1. A distributor comprising a sealed envelope containing a thermioniccathode, a plurality of anodes and a plurality of control electrodeslocated within the path of the cathode discharge and overlapped-collectively presenting an electrically effectively continuous controlelectrode surface, whereby discontinuity in the electrostatic controlfield is eliminated under operation and said discharge is distributed topredetermined ones of said anodes.

2. A distributor comprising a sealed envelope, a thermionic cathodewithin said envelope, aplurality of anodes collectively presenting anelectrically effectively continuous discharge surface for the electronstream, a plurality of control electrodes between said cathode and saidsubstantially continuous discharge surface, and means including saidcontrol electrodes to direct the electron stream against said continuousdischarge surface.

3. A distributor comprising a sealed envelope, a thermionic cathodewithin said envelope, a plu rality of anodes collectively presenting anelectrically effectively continuous discharge surface surrounding saidcathode, a grid structure between said cathode and said anodes, andmeans including said grid structure to direct the electron streamagainst a predetermined anode.

4. A distributor comprising a sealed envelope, a cathode in saidenvelope, a plurality of anodes collectively presenting an electricallyeffectively continuous discharge surface in said envelope surroundingsaid cathode, a plurality of grids between said cathode and said anodes,means for causing said cathode to emit an electron stream,

stream to said anodes in a ,electrons radially within a plane at rightangles to a geometric axis of said cathode, a plurality of anodesdisposed about said axis, a plurality of overlapping control electrodeselectrostatically operative within aforesaid plane and adapted topolyphase excitation.

7. A distributor comprising a sealed envelope containing a thermioniccathode adapted to emit electrons radially withina plane at right anglesto a geometric axis of said distributor, a plurality of anodes disposedabout said axis and passing through said plane, and means including aplurality of control electrodes to cause the emitted electrons to flowin a quantitatively substantially uniform stream continuously radiallyfrom said axis and simultaneously to revolve about said axis and withinsaid excitation.

8. A distributor comprising a sealed envelope containing a thermioniccathode surrounded by plane under a plurality of anodes and a pluralityof overlapping grids disposed between said cathode and said anodes, saidplurality of grids collectively presenting an electrically effectivelycontinuous control electrode surface for the electron discharge.

9. A distributor comprising a sealed envelope containing a thermioniccathode, a plurality of anodes arranged in a complete circle anddisposed about a thermionic cathode and an even number of controlelectrodes between said cathode and said anodes, the effective length ofthe electron discharge path from the aforesaid oath-- ode being lessthan the diameter of the said' anode circle.

citation under operation.

10. A distributor adapted to muIti-circuit' operation comprising acathode, a plurality of an- .odes and a plurality of control electrodes,said control electrodes collectively presenting an electricallyeffectively continuous control electrode surface to the said cathode.

11. A distributor adapted to multi-circuit operation comprising acathode anda plurality of anodes, said plurality of anodes collectivelypresenting an electrically effectively continuous discharge surface'tosaid cathode.

12. A distributor comprising a sealed envelope containing a thermioniccathode adapted to emit electrons radially within a plane atright anglesto a geometric axis of said distributor, a plurality of anodes disposedabout said axis and passing through said plane, and a plurality ofcontrol electrodes disposed between said cathode and said anodes andcollectively presenting a surface offering a substantially uniformcathodecontrol-electrode impedance for any radial instantaneous positionof the electron'stream about the aforesaid axis under operation.

13. A distributor comprising a sealed envelope containing a thermioniccathode adapted to emit electrons radially within a plane at rightangles to a geometric axis of said distributor, a plurality of controlelectrodes disposed about said cathode and passing through said plane,and a plurality of anodes disposed about said control electrodes andopposite the side thereof facing the aforesaid cathode and collectivelypresenting a surface offering a substantially uniform cathode-anodeimpedance for any radial instantaneous position of the electron streamabout the aforesaid axis under operation.

14. A distributor comprising a sealed envelope containing a thermioniccathode adapted to emit electrons radially within a plane at rightangles to ageoinetric axis of said distributor, a plurality of anodesdisposed aboutsaid axis and passing through said plane, a plurality ofcontrol electrodes disposed between said cathode and said anodes, saidanodes and said'control electrodes collectively presenting surfacesofiering.

substantially uniform distributor impedance for any radial instantaneousposition of the electron stream about the aforesaid axis ,for a givenex-

